Action de in rem verso is an action for unjust enrichment. In an action de in rem verso, the plaintiff should show that enrichment was bestowed, that the enrichment caused an impoverishment, that there is no justification for the enrichment and impoverishment, and that the plaintiff has no other adequate remedy at law, including no remedy under an express or implied contract. In Roman law, action de in rem verso is an action brought against a paterfamilias or a slave-owner who benefited from the transaction of a child or slave.